Building a bigger Shapeoko router

Hackaday alumni [Will O’Brien] sent in a few projects he’s been working on lately while he’s in the process of upgrading his workspace. He’s building a 1200 x 1200 mm CNC router based on the Shapeoko router, and it sure looks like he’s having fun doing it.

The Shapeoko router is based on the Makerslide open source linear bearing system. This system uses common aluminum extrusions as the frame of a very simple, very inexpensive CNC router. The Makerslide system is designed to be expandable; if you want a larger axis, just bolt in a longer piece of aluminum extrusion. We haven’t seen many Makerslide builds take advantage of this fact, a shame as the stock Shapeoko only has a build area of 200 mm square.

[Will] is expanding this build area to 1200 mm square, but of course this means beefing up some parts of the build. He’s already moved up to very hefty 250 oz/in Nema 23 stepper motors (up from the Nema 17s for a standard Shapeoko), as well as beefing up the motor mount a great deal.

[Will] also sourced a few lengths of cable drag chain (yes, that’s what it’s called) to keep all the wires for his huge CNC routers out of the path of a moving gantry and spinning motors. It looks like he’s got a very nice build shaping up, and we can’t wait to see it in action.

Super beefy motors, indeed, do not seem to be strictly necessary. Improbable Construct, who built the first 1meter^2+ Shapeoko , only used (fairly high torque) Nema 17’s and his setup works extremely well.

Your second thought is heading on the right track. Although it is not the cables but the guide rails that are the bulk of the increased load. So your train analogy breaks down when one axis carries another, because trains don’t carry other trains on their tracks, on themselves like CNC machines do. Plus when you scale a CNC machine up unless you’re very patient most people want faster rapid moves. Then the time it takes to traverse the length an axis stays the same.

For what its worth, I just finished building my 4′x4′ MakerSlide CNC router with 260 oz/in NEMA 23′s, but only used a single MakerSlide on the Y axis. After playing with it for a week, I was noticing quite a bit of “bounce” in the Y axis when the router touched down (enough to shake the whole table on some pieces). I decided to disassemble the Y axis to double it up, similar to this large Shapeoko router. At the same time, I doubled up the Z axis, as there was some flexing there as well. It seems much sturdier now. Hooking the motors back up next week for a test.